CN112566963A

CN112566963A - Polyimide film and flexible device using the same

Info

Publication number: CN112566963A
Application number: CN201980053238.1A
Authority: CN
Inventors: 尹哲民
Original assignee: LG Chem Ltd
Current assignee: LG Chem Ltd
Priority date: 2018-08-20
Filing date: 2019-08-19
Publication date: 2021-03-26
Anticipated expiration: 2039-08-19
Also published as: JP2021534275A; KR102279081B1; KR20200021410A; CN112566963B

Abstract

The polyimide film of the present invention is produced from a polyamic acid prepared using at least two tetracarboxylic dianhydrides as polymerization components, and a diamine containing diaminodiphenyl sulfone (DDS) and an amine-terminated methylphenyl siloxane oligomer. It is possible to provide a flexible device in which mechanical defects such as cracks do not occur in a low temperature poly-silicon (LTPS) thin film layer even during a high temperature process such as a LTPS process by adjusting the pore distribution ratio in a polyimide film to 1% or less and/or by adjusting the average size of phase separation domains in a polyimide film to 10nm or less.

Description

Polyimide film and flexible device using the same

Technical Field

The disclosures of the priority rights of korean patent application nos. 10-2018-0096802 and 10-2018-0096803, filed on 20.8.2018, and korean patent application No. 10-2019-0100199, filed on 16.8.2019, are hereby incorporated by reference in their entireties.

The present invention relates to a polyimide film having excellent heat resistance during high temperature processes and a flexible device using the same.

Background

In recent years, weight reduction and miniaturization of products have been emphasized in the field of displays. However, glass substrates are heavy and fragile and are difficult to apply to continuous processes. Therefore, research is actively conducted to apply a plastic substrate, which has advantages of being lightweight, flexible, and applicable to a continuous process, and can replace a glass substrate, to a cellular phone, a notebook computer, and a PDA.

In particular, the Polyimide (PI) resin has advantages in that it is easily synthesized, can be formed into a thin film, and does not require a crosslinking agent for curing. Recently, polyimide is widely used as a material for integration in semiconductors such as LCDs and PDPs, etc., due to weight reduction and precision of electronic products. In particular, many studies have been made to apply PI to a flexible plastic display panel having lightweight and flexible characteristics.

A Polyimide (PI) film produced by forming a polyimide resin into a film is generally prepared by: an aromatic dianhydride is polymerized with an aromatic diamine or an aromatic diisocyanate solution to prepare a solution of a polyamic acid derivative, the solution is coated on a silicon wafer or glass, and is cured (imidized) by heat treatment.

Flexible devices involving high temperature processes require heat resistance at high temperatures. In particular, an Organic Light Emitting Diode (OLED) using a Low Temperature Polysilicon (LTPS) process may have a process temperature close to 500 ℃. However, at this temperature, thermal decomposition by hydrolysis tends to occur even in the case of polyimide having excellent heat resistance. Therefore, development of a polyimide film that can exhibit excellent heat resistance is required to produce a flexible device.

Disclosure of Invention

Technical problem

The problem to be solved by the present invention is to provide a polyimide film having improved heat resistance at high temperatures.

Another problem to be solved by the present invention is to provide a flexible display using a polyimide film and a method of manufacturing the same.

Technical scheme

In order to solve the problems of the present invention,

polyimide films are provided that comprise the polymerized and imidized product of a polymeric component,

the polymeric component comprises: a diamine component comprising a diamine having the structure of formula 1 below and an amine-terminated methylphenylsiloxane oligomer; and a dianhydride component containing two or more tetracarboxylic dianhydrides, wherein the distribution ratio of pores in the film is 1% or less,

[ formula 1]

In addition, the present invention provides a polyimide film comprising a product of polymerization and imidization of a polymeric component,

the polymeric component comprises: a diamine component comprising a diamine having the structure of formula 1 and an amine-terminated methylphenylsiloxane oligomer; and a dianhydride component containing two or more tetracarboxylic dianhydrides,

wherein a plurality of domains derived from the amine-terminated methylphenylsiloxane oligomer are dispersed in the polyimide matrix derived from the diamine of formula 1, and an average size of the plurality of domains is 10nm or less.

According to one embodiment, the amine-terminated methylphenyl siloxane oligomer may have the structure of formula 2 below.

[ formula 2]

Wherein p and q are mole fractions, and when p + q is 100, p is 70 to 90, and q is 10 to 30.

According to one embodiment, the dianhydride component may contain biphenyl tetracarboxylic dianhydride (BPDA) and pyromellitic dianhydride (PMDA).

According to one embodiment, the dianhydride component may contain BPDA and PMDA in a molar ratio of 6:4 to 8: 2.

According to one embodiment, the polymeric component may comprise 5 to 30 wt% of the amine-terminated methylphenyl siloxane oligomer, based on the total weight of the total polymeric components.

According to one embodiment, the polymeric component may comprise 1 to 10 mole% of the amine-terminated methylphenyl siloxane oligomer, based on the total diamine component.

According to one embodiment, the polyimide film may have a modulus of 2.2Gpa or less and an elongation of 20% or more.

According to one embodiment, the glass transition temperature (Tg) of the polyimide film may be 230 ℃ or more.

In addition, the present invention provides a flexible device including the polyimide film.

In addition, the present invention provides a method for manufacturing a flexible device, comprising the steps of:

reacting a diamine component comprising a diamine of formula 1 and an amine-terminated methylphenylsiloxane oligomer with a dianhydride component comprising two or more tetracarboxylic dianhydrides to produce a polyimide precursor composition;

applying the prepared polyimide precursor composition on a carrier substrate;

heating and imidizing a polyimide precursor composition to form a polyimide film;

forming a device on the polyimide film; and

the polyimide film with the devices formed thereon is peeled off from the carrier substrate.

According to one embodiment, the method may include one or more processes selected from a Low Temperature Polysilicon (LTPS) thin film forming process, an ITO thin film forming process, or an oxide thin film forming process.

Advantageous effects

In the present invention, a diamine containing diaminodiphenyl sulfone (DDS) and an amine-terminated methylphenylsiloxane oligomer, and two or more tetracarboxylic dianhydrides are used as polymerization components, and the distribution ratio of pores in the film is adjusted to 1% or less, and/or the size of phase separation domains is adjusted to 10nm or less. Accordingly, the present invention can provide a flexible device that does not generate mechanical defects such as cracks in an inorganic film formed in a high temperature process such as a Low Temperature Polysilicon (LTPS) process, an ITO process, or an oxide process.

Drawings

Fig. 1 shows a method of measuring a distribution ratio of holes in a polyimide film from a focused ion beam scanning electron microscope (FIB-SEM) image of the polyimide film.

Fig. 2 is a view for explaining a method of measuring a distribution ratio of phase separation domains from a focused ion beam scanning electron microscope (FIB-SEM) image of a polyimide film.

Fig. 3 shows a FIB-SEM image of the polyimide film according to comparative example 1.

Fig. 4a to 4c compare FIB-SEM images at the same DPS-DMS content with respect to polyimide films according to comparative examples and examples.

Fig. 5 is a FIB-SEM image of the polyimide films according to examples 11, 13, 14 and 15.

FIG. 6 is a view showing that SiO is performed on the polyimide films according to comparative examples 3 and 4 and example 1₂Photographs of the state after deposition and heat treatment.

Detailed Description

Since numerous modifications and variations can be made in the present invention, specific embodiments are shown in the drawings and will be described in detail in the detailed description. It should be understood, however, that the intention is not to limit the invention to the particular embodiments, but to include all modifications, equivalents, and alternatives falling within the spirit and scope of the invention. In the following description of the present invention, a detailed description of known functions will be omitted if it may obscure the subject matter of the present invention.

In the present disclosure, all compounds or organic groups may be substituted or unsubstituted, unless otherwise specified. Herein, the term "substituted" means that at least one hydrogen contained in a compound or organic group is substituted with a substituent selected from the group consisting of: a halogen atom, an alkyl group having 1 to 10 carbon atoms, a haloalkyl group, a cycloalkyl group having 3 to 30 carbon atoms, an aryl group having 6 to 30 carbon atoms, a hydroxyl group, an alkoxy group having 1 to 10 carbon atoms, a carboxyl group, an aldehyde group, an epoxy group, a cyano group, a nitro group, an amino group, a sulfonic acid group, or a derivative thereof.

According to one embodiment of the present invention, there is provided a polyimide film comprising the product of polymerization and curing of a polymeric component comprising: a diamine component comprising a compound of the following formula 1 and a methylsiloxane (DMS) -Dimethylsiloxane (DPS) oligomer modified at both ends with an amine, and

a dianhydride component containing two or more tetracarboxylic dianhydrides, wherein the distribution ratio of pores in the film is 1% or less.

[ formula 1]

According to another embodiment of the present invention, there is provided a polyimide film comprising the product of polymerization and imidization of a polymeric component comprising: a diamine component comprising the compound of formula 1 and a bis-terminal amine-modified methylsiloxane (DMS) -Dimethylsiloxane (DPS) oligomer, and

a dianhydride component comprising two or more tetracarboxylic dianhydrides, wherein a plurality of domains derived from an amine-terminated methylphenylsiloxane oligomer are dispersed in a polyimide matrix derived from a diamine of formula 1, and the plurality of domains have an average size of 10nm or less.

The compound represented by formula 1 may be at least one selected from the group consisting of 4,4- (diaminodiphenyl) sulfone (hereinafter, 4,4-DDS), 3,4- (diaminodiphenyl) sulfone (hereinafter, 3,4-DDS), and 3,3- (diaminodiphenyl) sulfone (hereinafter, 3, 3-DDS).

In the present invention, by using diaminodiphenyl sulfone (DDS) of formula 1 together with an amine-terminated methylphenylsiloxane oligomer as a polymerization component in the preparation of polyamic acid, the ratio of pores that may occur during the manufacturing process of a polyimide film containing a siloxane oligomer structure can be significantly reduced. The pores formed in the polyimide film may cause cracks in the inorganic film formed later on the polyimide film, which is not preferable.

In the manufacturing process of a polyimide film including an amine-terminated methylphenyl siloxane oligomer structure, chain scission and rearrangement of the siloxane oligomer structure may occur during a high-temperature curing process, thereby generating pores in the polyimide film. In this regard, a polyimide having a structure with a high modulus, i.e., a polyimide having a rigid structure, does not have high fluidity at high temperature, and thus pores generated in the above process may remain in the film. Thus, the ratio of pores present in the membrane will be higher. However, the polyimide film according to the present invention uses a diamine containing a flexible structure, such as diaminodiphenyl sulfone (DDS), and thus has high fluidity at high temperature, and thus can discharge pores generated during film formation to the outside. Therefore, the ratio of pores present in the film can be significantly reduced.

At this time, the distribution ratio of the pores can be measured as follows.

When a FIB-SEM image of 100,000 magnifications of the polyimide film was fixed to 100mm × 80mm and the subdivision was 2mm × 2mm, the distribution ratio of the holes was calculated as a ratio of the area where the holes were present with respect to the entire 2000 areas. Fig. 1 shows a method of measuring the distribution ratio of holes using a FIB-SEM image.

For example, if there are two regions (2) where holes are present, the distribution ratio of the holes is as follows.

The distribution ratio (%) of the pores was 2/2000X 100: 0.1%

Since polyimide chains containing siloxane structures such as amine-terminated methylphenyl siloxane oligomers may exhibit polarity, phase separation may occur due to the difference in polarity from polyimide chains that do not contain siloxane structures, resulting in non-uniform distribution of siloxane structures in the polyimide matrix. In this case, it is difficult to exhibit an improvement effect of physical properties of polyimide, such as strength increase and stress release effect, due to the siloxane structure, and transparency of the film may be deteriorated due to an increase in haze caused by phase separation. In particular, when the diamine containing a siloxane oligomer structure has a high molecular weight, polyimide chains prepared therefrom exhibit more pronounced polarity, and the phenomenon of phase separation between polyimide chains may occur more clearly. However, in order to solve these problems, when a siloxane oligomer having a low molecular weight structure is used, a large amount of the siloxane oligomer should be added to exhibit effects such as stress relaxation. This may cause problems such as Tg at low temperature, and thus physical properties of the polyimide film may be deteriorated.

Therefore, in the present invention, by using the diamine of formula 1 together with the amine-terminated methylphenylsiloxane oligomer, the siloxane oligomer structure can be more uniformly distributed in the polyimide matrix without phase separation.

According to an aspect of the present invention, there is provided a polyimide film in which an average size of phase separation domains generated from a polyimide comprising an amine-terminated methylphenylsiloxane-derived structure is adjusted to 10nm or less. In this case, the phase separation domain refers to an amine-terminated methylphenylsiloxane domain distributed in a polyimide matrix. The size of the phase separation domain refers to the maximum diameter of the white circle surrounding the corresponding region in a focused ion beam scanning electron microscope (FIB-SEM) image of polyimide.

The average size of the phase separation domains in the polyimide film according to the present invention is 10nm or less, for example, it means phase separation domains having a very small size of 1nm to 10nm, i.e., domains derived from amine-terminated methylphenylsiloxane. Since the size of phase separation in the polyimide film is 10nm or less, a continuous phase is possible, thereby minimizing residual stress while maintaining heat resistance and mechanical characteristics. Without such a continuous phase, there may be an effect of reducing residual stress, but it is difficult to use for the process due to significant reduction in heat resistance and mechanical properties.

The moieties (domains) comprising amine-terminated methylphenylsiloxane structures are connected in series in the polyimide matrix. The continuous phase refers to a shape in which nano-sized domains are uniformly distributed in a polyimide matrix.

Therefore, in the present invention, phase separation caused by amine-terminated methylphenylsiloxane occurs by using DDS (diaminodiphenylsulfone) of formula 1 together with amine-terminated methylphenylsiloxane oligomer as a polymerization component in the production of polyamic acid. However, the average size thereof may be very small, for example, 10nm or less, and the phase separation domains are uniformly distributed in the polyimide matrix, thereby reducing problems that may be caused due to phase separation. For example, the occurrence of haze, which may occur due to phase separation, may be reduced, and thus a polyimide having more transparent characteristics may be obtained. In addition, since the amine-terminated methylphenylsiloxane structure exists as a continuous phase, the mechanical strength and stress release effect of the polyimide can be improved. Due to these characteristics, the polyimide film according to the present invention may have not only optical characteristics but also a reduced degree of warpage of the substrate after coating-curing, thereby providing a flat polyimide film.

In the polyimide film, the distribution ratio of the phase separation domains contained in the polyimide film may be about 25% to 60%, preferably 50% or less, or 40% or less.

As shown in fig. 2, when the FIB-SEM image of 100,000 magnifications was fixed at 100mm × 70mm, the subdivision was 2mm × 2mm, and each area was divided into a white area and a black area, the distribution ratio of the areas was calculated as the ratio of the white area to the entire area.

For example, when the number of total areas is 1750 and the number of white areas is 650, it may be calculated as follows:

the distribution ratio of the phase separation domain is (650/1750) × 100 is 32%.

In the polyimide film, when the distribution ratio of the phase separation measured as described above is 25% or less, the residual stress may be high, thereby causing warpage of the substrate during the TFT process, and when it is 60% or more, reduced Tg and haze (haze) may occur due to excessive phase separation.

[ formula 2]

According to an embodiment, the diamine of formula 2 may be added in an amount of 5 to 30 wt%, preferably 10 to 25 wt%, more preferably 10 to 20 wt%, with respect to the total weight of the solid content of the polyimide copolymer, i.e., the total weight of the polyimide resin precursor or the total weight of the polymerization components (the diamine component and the acid dianhydride component).

When the diamine comprising the structure of formula 2 is excessively added, mechanical properties of the polyimide, such as modulus, may be reduced and film strength may be reduced, thereby causing physical damage to the film, such as tearing, during the process. In addition, when the diamine having the structure of formula 2 is excessively added, it has a glass transition temperature (Tg) derived from the polymer having a siloxane structure. Therefore, a glassy state may occur at a low process temperature of 350 ℃ or less. During the deposition of the inorganic film at 350 c or more, wrinkles may be generated on the surface of the film due to a flow phenomenon of the polymer, and the inorganic film may be cracked.

The diamine compound having the structure of formula 2 may have a molecular weight of 4000g/mol or more. According to one embodiment, the molecular weight may be 5000g/mol or less, alternatively 4500g/mol or less. Here, the molecular weight means a weight average molecular weight, and can be calculated by calculating an amine equivalent using NMR analysis or acid-base titration.

When the molecular weight of the siloxane oligomer comprising the structure of formula 2 is less than 4000g/mol, heat resistance may be reduced, for example, the glass transition temperature (Tg) of the resulting polyimide is reduced or the thermal expansion coefficient is excessively increased.

According to one embodiment, the both-terminal diamine-modified siloxane oligomer may be included in an amount of 1 mol% to 20 mol% of the total diamine, preferably in an amount of 1 mol% or more and 10 mol% or less, or 5 mol%.

The polyimide film according to the present invention comprises two or more tetracarboxylic dianhydrides as polymerization components, and preferably comprises both biphenyl tetracarboxylic dianhydride (BPDA) and pyromellitic dianhydride (PMDA) as tetracarboxylic dianhydrides. Furthermore, it may be preferred to include BPDA and PMDA in a molar ratio of 6:4 to 8:2 or 5:5 to 7: 3.

In the polymerization of polyamic acid used to produce the polyimide film according to the present invention, the dianhydride component may further contain: tetracarboxylic dianhydrides other than BPDA and PMDA, for example tetracarboxylic dianhydrides comprising a tetravalent organic group selected from the structures of formulae 3a to 3 h.

[ formula 3a ]

[ formula 3b ]

[ formula 3c ]

[ formula 3d ]

[ formula 3e ]

[ formula 3f ]

[ formula 3g ]

[ formula 3h ]

In formulae 3a to 3h, R₁₁To R₂₄Each independently is a substituent selected from: halogen atoms selected from the group consisting of-F, -Cl, -Br and-I, hydroxyl groups (-OH), thiol groups (-SH), nitro groups (-NO)₂) Cyano, alkyl having 1 to 10 carbon atoms, haloalkoxy having 1 to 4 carbon atoms, haloalkyl having 1 to 10 carbon atoms and alkyl havingAryl of 6 to 20 carbon atoms.

a1 is an integer from 0 to 2, a2 is an integer from 0 to 4, a3 is an integer from 0 to 8, a4 and a5 are each independently an integer from 0 to 3, a7 and a8 are each independently an integer from 0 to 3, a10 and a12 are each independently an integer from 0 to 3, a11 is an integer from 0 to 4, a15 and a16 are each independently an integer from 0 to 4, a17 and a18 are each independently an integer from 0 to 4, and a6, a9, a13, a14, a19 and a20 are each independently an integer from 0 to 3,

n is an integer of 1 to 3, and

A₁₁to A₁₆Each independently selected from-O-, -CR 'R' -, -C (═ O) O-, -C (═ O) NH-, -S-, -SO₂-, phenylene, and combinations thereof, wherein R' and R "are each independently selected from the group consisting of a hydrogen atom, an alkyl group having 1 to 10 carbon atoms, and a fluoroalkyl group having 1 to 10 carbon atoms.

Here, in the formula, denotes a binding site.

In the polymerization of polyamic acid used to produce the polyimide film according to the present invention, the diamine component may further contain a diamine other than the DDS of formula 1 and the amine-terminated methylphenyl siloxane of formula 2, for example, a diamine having the structure of formula 4 below.

[ formula 4]

In formula 4

R₃₁And R₃₂Each independently is a substituent selected from: halogen atoms selected from the group consisting of-F, -Cl, -Br and-I, hydroxyl groups (-OH), thiol groups (-SH), nitro groups (-NO)₂) Cyano, alkyl having 1 to 10 carbon atoms, haloalkoxy having 1 to 4 carbon atoms, haloalkyl having 1 to 10 carbon atoms and aryl having 6 to 20 carbon atoms, preferably a substituent selected from the group consisting of a halogen atom, a haloalkyl group, an alkyl group, an aryl group and a cyano group. For example, the halogen atom may be fluorine (-F), and the haloalkyl group may be a fluorine atom-containing fluoroalkyl group having 1 to 10 carbon atoms, for example selected from fluoromethyl groupsPerfluoroethyl and trifluoromethyl, the alkyl group may be selected from methyl, ethyl, propyl, isopropyl, tert-butyl, pentyl and hexyl, and the aryl group may be selected from phenyl and naphthyl. More preferably, they may be substituted with a fluorine atom or a fluorine-based substituent (e.g., fluoroalkyl group) containing a fluorine atom.

Here, the "fluorine-based substituent" refers to "a fluorine atom substituent" and "a substituent containing a fluorine atom".

Q may be selected from the group consisting of a single bond, -O-, -CR' R "-, -C (═ O) O-, -C (═ O) NH-, -S-, -SO ═ O) O-, -C ═ O₂-, phenylene, and combinations thereof, wherein R' and R "are each independently selected from the group consisting of a hydrogen atom, an alkyl group having 1 to 10 carbon atoms, and a fluoroalkyl group having 1 to 10 carbon atoms.

The precursor composition for preparing the polyimide film according to the present invention may further comprise an adhesion promoter. The adhesion promoter may be included in an amount of 0.05 to 3 parts by weight, preferably 0.05 to 2 parts by weight, based on 100 parts by weight of the total solid content.

According to one embodiment, the adhesion promoter may comprise the structure of the following formula 5 or 6.

[ formula 5]

[ formula 6]

In the case of the formulas 5 and 6,

Q₁is a tetravalent organic radical having from 1 to 30 carbon atoms or from R_a-L-R_bA tetravalent organic radical of formula (I), wherein R_aAnd R_bEach independently a monovalent organic group selected from substituted or unsubstituted aliphatic having 4 to 10 carbon atoms, aromatic having 6 to 24 carbon atoms, and cyclic aliphatic having 3 to 24 carbon atoms, and L is selected from a single bond, -O-, -CR' R "-、-C(＝O)-、-C(＝O)O-、-C(＝O)NH-、-S-、-SO₂-, phenylene and combinations thereof, wherein R 'and R' are each independently selected from the group consisting of a hydrogen atom, an alkyl group having 1 to 10 carbon atoms, and a fluoroalkyl group having 1 to 10 carbon atoms, more preferably L is selected from the group consisting of-SO₂-, -CO-, -O-and C (CF)₃)₂。

Q₂Is a divalent organic radical having from 1 to 30 carbon atoms or R_c-L-R_dA divalent organic group represented by wherein R_cAnd R_dEach independently is a monovalent organic radical selected from the group consisting of substituted or unsubstituted aliphatic having 4 to 10 carbon atoms, aromatic having 6 to 24 carbon atoms, and cycloaliphatic having 3 to 24 carbon atoms, and L is selected from the group consisting of a single bond, -O-, -CR' R "-, -C (═ O) -, -C (═ O) O-, -C (═ O) NH-, -S-, -SO₂-, phenylene, and combinations thereof, wherein R' and R "are each independently selected from the group consisting of a hydrogen atom, an alkyl group having 1 to 10 carbon atoms, and a fluoroalkyl group having 1 to 10 carbon atoms.

R₁And R₃Each independently an alkyl group having 1 to 5 carbon atoms.

R₂And R₄Each independently a hydrogen atom or an alkyl group having 1 to 5 carbon atoms, more preferably an ethyl group.

a and b are each independently an integer of 1 to 3.

For example, Q₁May be a tetravalent organic group selected from the following formulas 5a to 5s, but is not limited thereto.

In formula 6, Q₂May be a divalent organic group selected from the following formulas 6a to 6t, but is not limited thereto.

The adhesion promoter comprising the structures of formulae 5 and 6 may not only improve adhesion to an inorganic layer but also have low reactivity with polyamic acid. When alkoxysilane-based additives such as ICTEOS and aptos, which are general adhesion improving additives, are added, an increase in viscosity caused by a side reaction between polyamic acid and the additive may be reduced, thereby improving storage stability at room temperature.

In high heat resistant polyimide used as a conventional flexible display substrate, in order to increase adhesion to a glass substrate or a glass substrate on which an inorganic layer is deposited as a carrier substrate, a method of coating an adhesion promoter on glass and forming a film has been used. However, the use of the conventional adhesion promoter is limited in that foreign substances are generated due to the application of the adhesion promoter or an additional coating process is required, and thus the process is economically inefficient. Further, even when the adhesion promoter is directly added to the polyimide resin precursor, there is a problem that the amino group and the carboxylic acid of the polyamic acid precipitate as a salt to thereby decrease the adhesion.

In addition, there is also a prior art that can improve adhesion by synthesizing an adhesion promoter and adding it directly to a polyimide precursor. However, since an acid anhydride having a relatively rigid structure is used, there is a problem that a phase retardation phenomenon occurs in a portion of the adhesion promoter after curing, resulting in an increase in retardation value in the thickness direction of the resulting polyimide film. In addition, in the case of using an adhesion promoter comprising a flexible structure such as ODPA (4, 4' -oxydiphthalic anhydride), the retardation value may not increase due to the flexibility of the structure, but Tg may tend to decrease.

According to a preferred embodiment, the adhesion promoter may have a fluorene skeleton. In this case, due to the fluorene skeleton, intermolecular free volume is generated while the adhesion enhancing effect is maintained to the maximum, which does not affect the packing density, thereby exhibiting isotropic characteristics. In addition, heat resistance is also excellent due to the structural feature of containing more aromatic. That is, even if the adhesion promoter is mixed with the polyimide resin precursor, precipitation does not occur, and the occurrence of foreign matter can be minimized. Therefore, it is possible to provide a polyimide film that is isotropic while having excellent adhesion to a substrate and not affecting a phase difference in the thickness direction (as optical characteristics after application and curing of the polyimide film).

According to one embodiment of the invention, the dianhydride component and the diamine component may be reacted in a molar ratio of 1:0.9 to 0.9:1, 1:0.98 to 0.98:1, or 1:0.99 to 0.99: 1. Preferably, the dianhydride component may be reacted in excess with respect to the diamine component, or the diamine component may be reacted in excess with respect to the dianhydride component, in order to improve reactivity and processability. According to a preferred embodiment, preferably, the dianhydride component is reacted in excess relative to the diamine component (e.g., dianhydride: diamine ═ 1:0.995 to 0.999).

In addition, the organic solvent that may be used for the polymerization reaction of polyamic acid may be selected from: ketones such as gamma-butyrolactone, 1, 3-dimethyl-imidazolidinone, methyl ethyl ketone, cyclohexanone, cyclopentanone, and 4-hydroxy-4-methyl-2-pentanone; aromatic hydrocarbons such as toluene, xylene, and tetramethylbenzene; glycol ethers (cellosolves) such as ethylene glycol monoethyl ether, ethylene glycol monomethyl ether, ethylene glycol monobutyl ether, diethylene glycol monoethyl ether, diethylene glycol monomethyl ether, diethylene glycol monobutyl ether, propylene glycol monomethyl ether, propylene glycol monoethyl ether, dipropylene glycol diethyl ether and triethylene glycol monoethyl ether; ethyl acetate, butyl acetate, ethylene glycol monoethyl ether acetate, ethylene glycol monobutyl ether acetate, diethylene glycol monoethyl ether acetate, dipropylene glycol monomethyl ether acetate, ethanol, propanol, ethylene glycol, propylene glycol, carbitol, Dimethylpropionamide (DMPA), Diethylpropionamide (DEPA), dimethylacetamide (DMAc), N-diethylacetamide, Dimethylformamide (DMF), Diethylformamide (DEF), N-methylpyrrolidone (NMP), N-ethylpyrrolidone (NEP), N-dimethylmethoxyacetamide, dimethyl sulfoxide, pyridine, dimethyl sulfone, hexamethylphosphoramide, tetramethylurea, N-methylcaprolactam, tetrahydrofuran, m-di-N-butyl acetate, ethylene glycol monoethyl ether acetate, ethylene glycol monobutyl ether acetate, diethylene glycol monoethyl ether acetate, dipropylene glycol monomethyl ether acetate, ethanol, propanol, ethylene glycol, propylene glycol

Alkane, para-di

Alkane, 1, 2-dimethoxyethane, bis (2-methoxyethyl) ether, 1, 2-bis (2-methoxyethoxy) ethane, bis [2- (2-methoxyethoxy)]Ether, Equamide M100, Equamide B100, etc., and these solvents may be used alone or as a mixture of two or more.

For example, the organic solvent that can be used for the polymerization reaction of the diamine and the acid dianhydride may have a positive partition coefficient (LogP value) at 25 ℃, and a boiling point of 300 ℃ or less. More specifically, the partition coefficient Log P value may be 0.01 to 3, or 0.01 to 2, or 0.1 to 2.

The distribution coefficients may be calculated using an ACD/LogP module from the ACD/Percepta platform of ACD/Labs. The ACD/LogP module uses an algorithm based on a QSPR (Quantitative Structure-Property Relationship) method using a 2D molecular Structure. The distribution coefficient (LogP value) at 25 ℃ of representative solvents is as follows.

The solvent having a positive partition coefficient (LogP) may be at least one selected from the group consisting of Dimethylpropionamide (DMPA), Diethylpropionamide (DEPA), N-diethylacetamide (DEAc), N-Diethylformamide (DEF), and N-ethylpyrrolidone (NEP), particularly an amide-based solvent.

The reaction of the tetracarboxylic dianhydride with the diamine can be carried out by a conventional polymerization method of the polyimide resin precursor, for example, solution polymerization. Specifically, it can be prepared by dissolving a diamine in an organic solvent and then polymerizing by adding a tetracarboxylic dianhydride to the resulting mixed solution.

The polymerization reaction may be carried out in a flow of inert gas or nitrogen, and may be carried out under anhydrous conditions.

The reaction temperature during the polymerization reaction may be-20 ℃ to 80 ℃, preferably 0 ℃ to 80 ℃. If the reaction temperature is too high, reactivity may become high and the molecular weight may become large, and the viscosity of the precursor composition may increase, which may be disadvantageous in terms of process.

The polyimide resin precursor composition including the polyamic acid may be in the form of a solution dissolved in an organic solvent. For example, when the polyimide resin precursor is synthesized in an organic solvent, the solution may be a reaction solution obtained as it is, or may be a reaction solution obtained by diluting the reaction solution with another solvent. When the polyimide precursor is obtained as a solid powder, it may be dissolved in an organic solvent to prepare a solution. For example, the organic solvent used for the polymerization reaction may be an organic solvent having a positive LogP, and the organic solvent to be mixed later may be an organic solvent having a negative LogP.

According to one embodiment, the solid content of the composition may be adjusted by adding an organic solvent so that the content of the total polyimide resin precursor is 8 to 25% by weight, preferably 10 to 25% by weight, more preferably 10 to 20% by weight or less.

Alternatively, the polyimide resin precursor composition may be adjusted to have a viscosity of 2,000cP or higher, or 3,000cP or higher, or 4,000cP or higher. The viscosity of the polyimide resin precursor composition is 10,000cP or less, preferably 9,000cP or less, and more preferably 8,000cP or less. When the viscosity of the polyimide resin precursor composition exceeds 10,000cP, defoaming efficiency is reduced during the treatment of the polyimide film. This not only results in reduced process efficiency, but also in deterioration of surface roughness of the produced film due to bubble generation. This may lead to degraded electrical, optical and mechanical properties.

The weight average molecular weight of the polyimide according to the present invention may be 10,000 to 200,000g/mol, or 20,000 to 100,000g/mol, or 30,000 to 100,000 g/mol. The molecular weight distribution (Mw/Mn) of the polyimide according to the present invention is preferably 1.1 to 2.5. The weight average molecular weight (Mw) and number average molecular weight (Mn) were calculated by gel permeation chromatography based on polystyrene standards. When the weight average molecular weight or molecular weight distribution of the polyimide is outside the above range, film formation may be difficult, or characteristics of the polyimide film such as transmittance, heat resistance, and mechanical characteristics may be deteriorated.

Then, the polyimide resin precursor resulting from the polymerization reaction may be imidized to prepare a transparent polyimide film.

According to one embodiment, the polyimide film may be manufactured by a method including the steps of:

applying a polyimide resin precursor composition to a substrate; and

the applied polyimide resin precursor composition is subjected to a heat treatment.

As the substrate, a glass substrate, a metal substrate, a plastic substrate, or the like can be used without any particular limitation. Among them, a glass substrate may be preferable, which is excellent in thermal stability and chemical stability during imidization and curing processes of a polyimide precursor, and which can be easily separated without any treatment even with an additional release agent while a polyimide film formed after curing is not damaged.

The application process can be carried out according to conventional application methods. Specifically, a spin coating method, a bar coating method, a roll coating method, an air knife method, a gravure method, a reverse roll method, a kiss roll method, a doctor blade method, a spray coating method, a dipping method, a brush coating method, or the like can be used. Among them, it is more preferable to carry out by a casting method which allows a continuous process and can improve the imidization rate of polyimide.

Further, the polyimide resin precursor composition may be applied on the substrate in such a thickness that the finally produced polyimide film has a thickness suitable for the display substrate.

Specifically, it may be applied in an amount such that the thickness is 10 μm to 30 μm. After the polyimide resin precursor composition is applied, a drying process for removing a solvent remaining in the polyimide resin precursor composition may be further optionally performed before the curing process.

The drying process may be carried out according to a conventional method. Specifically, the drying process may be performed at a temperature of 140 ℃ or less or 80 ℃ to 140 ℃. If the drying temperature is lower than 80 deg.C, the drying process becomes longer. If the drying temperature exceeds 140 ℃, imidization partially proceeds, making it difficult to form a polyimide film having a uniform thickness.

Then, the polyimide resin precursor composition is applied on a substrate and heat-treated in an IR oven, in a hot air oven or on a hot plate. The heat treatment temperature may be 300 ℃ to 500 ℃, preferably 320 ℃ to 480 ℃. The heat treatment may be performed in a multi-step heating process within the above temperature range. The heat treatment process may be performed for 20 minutes to 70 minutes, preferably 20 minutes to 60 minutes.

Thereafter, the polyimide film may be produced by peeling the polyimide film from the substrate according to a conventional method.

The polyimide film prepared as described above may have a modulus of 2.2Gpa or less, for example, 0.1Gpa to 2.0Gpa, and an elongation of 20% or more. When the elastic modulus is less than 0.1GPa, the film has low rigidity and is easily broken by external impact. When the elastic modulus exceeds 2.2GPa, the film may have high rigidity, but may not ensure sufficient flexibility.

In addition, the glass transition temperature (Tg) of the polyimide film according to the present invention may be 230 ℃ or more.

In addition, the polyimide film according to the present invention may have excellent thermal stability against temperature change. For example, after n +1 heating and cooling processes in a temperature range of 100 ℃ to 400 ℃, the coefficient of thermal expansion may be-10 ppm/DEG C to 100 ppm/DEG C, preferably-7 ppm/DEG C to 90 ppm/DEG C, more preferably 80 ppm/DEG C or less.

In addition, the retardation value (R) in the thickness direction of the polyimide film according to the present invention_th) May be about-100 nm to +100nm, thereby exhibiting isotropic characteristics and improving visibility.

According to one embodiment, the adhesion force of the polyimide film to the carrier substrate may be at least 5gf/in, preferably at least 10 gf/in.

applying a precursor composition comprising a polyamic acid prepared from a diamine comprising diaminodiphenyl sulfone (DDS) and an amine-terminated methylphenyl siloxane oligomer, and two or more tetracarboxylic dianhydrides as polymeric components on a carrier substrate;

heating the precursor composition to imidize the polyamic acid, thereby forming a polyimide film;

forming a device on the polyimide film; and

In particular, the process of manufacturing the flexible device may include a Low Temperature Polysilicon (LTPS) thin film forming process, an ITO thin film forming process, or an oxide thin film forming process.

For example, a flexible device comprising an LTPS layer may be obtained by: the carrier substrate and the polyimide film are peeled by an LTPS thin film manufacturing process including:

forming SiO-containing film on polyimide film₂The barrier layer of (1);

depositing an a-Si (amorphous silicon) film on the barrier layer;

performing dehydrogenation annealing by heat-treating the deposited a-Si thin film at a temperature of 450 ℃ + -50 ℃; and crystallizing the a-Si thin film using an excimer laser or the like.

The holes in the polyimide film may cause cracks on the inorganic film (polysilicon thin film) through a high temperature heat treatment process in a Low Temperature Polysilicon (LTPS) TFT process. Accordingly, the present invention can suppress or significantly reduce the occurrence of cracks in the inorganic film layer by adjusting the ratio of pores in the polyimide film to 1% or less and/or adjusting the average size of the phase separation domains to 10nm or less.

The oxide thin film forming process may be heat-treated at a lower temperature than the process using silicon. For example, the heat treatment temperature of the ITO TFT process may be 200 ℃ + -50 ℃, and the heat treatment temperature of the oxide TFT process may be 320 ℃ + -50 ℃.

EMBODIMENTS FOR CARRYING OUT THE INVENTION

Hereinafter, embodiments of the present invention will be described in detail so that those skilled in the art can easily practice the present invention. This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein.

< example 1> BPDA-PMDA (6:4)/DDS/DPS-DMS 10% by weight%

After DEAc (N, N-diethylacetamide) was charged into the reactor under a nitrogen stream, 0.15096mol of 4,4 '-DDS (4, 4' -diaminodiphenyl sulfone) was added and dissolved while maintaining the temperature of the reactor at 25 ℃. To the DDS-added solution were added 0.0611mol of PMDA (pyromellitic dianhydride) and 0.0917mol of BPDA (3,3 ', 4, 4' -biphenyltetracarboxylic dianhydride) at the same temperature, and stirred for 24 hours. Then, 0.00199mol of DPS-DMS (diphenylsiloxane-dimethylsiloxane co-oligomer, molecular weight 4360g/mol) modified at both ends with an amine were added and stirred at 80 ℃ for 4 hours. Thereafter, the oil bath was removed and the temperature was returned to room temperature to obtain a transparent DEAc solution of polyamic acid.

< examples 2 to 12> BPDA-PMDA/DDS/DPS-DMS

A DEAc solution of polyamic acid was prepared in the same manner as in example 1 except that the molar ratio of BPDA to PMDA and the amount of DPS-DMS added were changed as described in tables 1 to 3.

< examples 13 to 15>

A polyamic acid solution was prepared in the same manner as in example 9, except that the DPS-DMS contents were set to 25 wt%, 20 wt%, and 5 wt%, respectively.

< comparative example 1> BPDA _ PMDA (6:4) _ DDS

After DEAC was charged into the reactor under a nitrogen stream, 0.08497mol of 4, 4' -DDS was added and dissolved while maintaining the temperature of the reactor at 25 ℃. To the DDS-added solution were added 0.03399mol of PMDA and 0.005098mol of BPDA at the same temperature, and stirred for 24 hours to obtain a transparent DEAC solution of polyamic acid.

< comparative example 2> BPDA _ PMDA (6:4)/TFMB/DPS-DMS 10% by weight

After DEAc was charged into the reactor under a nitrogen stream, 0.1121mol of TFMB (2, 2' -bis (trifluoromethyl) benzidine) was added and dissolved while maintaining the temperature of the reactor at 25 ℃. To the solution to which TFMB was added, 0.0453mol of PMDA and 0.0679mol of BPDA were added at the same temperature, and stirred for 24 hours. Then, 0.00168mol of DPS-DMS (molecular weight 4360g/mol) both ends of which were modified with an amine was added and stirred at 80 ℃ for 4 hours. Thereafter, the oil bath was removed and the temperature was returned to room temperature to obtain a transparent DEAc solution of polyamic acid.

< comparative example 3> BPDA _ PMDA (6:4)/TFMB/DPS-DMS 15% by weight

A transparent polyamic acid DEAC solution was prepared in the same manner as in comparative example 2, except that the amount of DPS-DMS added was changed to 15% by weight.

< comparative example 4> BPDA _ PMDA (6:4)/TFMB/DPS-DMS 18% by weight

A transparent polyamic acid DEAC solution was prepared in the same manner as in comparative example 2, except that the amount of DPS-DMS added was changed to 18% by weight.

< Experimental example 1>

Each of the polyimide resin precursor solutions prepared in examples 1 to 12 and comparative examples 1 to 4 was spin-coated on a glass substrate. The glass substrate coated with the polyimide precursor solution was placed in an oven, heated at a rate of 5 ℃/min, cured at 80 ℃ for 30 minutes, and cured at 400 ℃ for 30 minutes to prepare a polyimide film. The characteristics of each film were measured and are shown in tables 1 to 3 below.

< viscosity >

The viscosity of the solution was measured by using a plate rheometer (model LVDV-1II Ultra, Brookfield) in a vessel containing 5ml of PAA solution with a reduced rotor (spindle) and adjusting the rpm. After waiting for 1 minute after the torque reached 80, the viscosity value was measured at which the torque did not change. At this time, the rotor used was 52Z, and the temperature was 25 ℃.

< ratio of pore distribution >

When a FIB-SEM (focused ion beam scanning electron microscope) image of 100,000 magnification of the polyimide film was fixed to 100mm × 80mm and the subdivision was 2mm × 2mm, the distribution ratio of the holes was calculated as a ratio of the area where the holes were present with respect to the entire 2000 areas (see fig. 1).

Fig. 1 shows a method of measuring the distribution ratio of pores using a FIB-SEM image of the film according to example 4. Since there are 2 regions where pores exist, the distribution ratio of the pores is 0.1%. The distribution ratio of pores [ < 2/2000 ]. times.100 [ < 0.1% ]

FIG. 3 shows a FIB-SEM of the polyimide film of comparative example 1 in which the polyimide does not comprise DPS-DMS. As can be seen from fig. 3, in the case where the polyimide does not contain DPS-DMS, no pores are present in the membrane.

FIGS. 4a to 4c show FIB-SEM images of polyimide films of examples and comparative examples according to the content variation of DPS-DMS. In the case of containing DPS-DMS, it can be seen that the generation amount of pores greatly increases as the content of DPS-DMS increases for the polyimide film of the comparative example, but it can be seen that pores are hardly generated for the polyimide film of the example containing DDS as diamine even though the content of DPS-DMS increases. Specifically, fig. 4a shows a comparison of the films of example 4 and comparative example 4 in which the content of DPS-DMS is 18 wt%. The distribution ratio of pores of example 4 was 0.1%, wherein the area of pores was 2, while comparative example 4 showed a very high distribution ratio of pores of 21%, and comparative example 2 showed a distribution ratio of pores of 4.6%.

< Yellowness Index (YI) >

The Yellowness Index (YI) was measured using Color Eye 7000A.

< haze >

Haze was measured by using a haze meter HM-150 according to the method of ASTM D1003.

< transmittance >

The transmittance was measured for wavelengths of 450nm, 550nm and 633nm using a transmittance meter (model name HR-100, Murakami Color Research Laboratory) based on JIS K7105.

Measurement of retardation in the thickness direction (R) by Axoscan_th). The film was cut to size and the thickness was measured. Then, the retardation value was measured using Axoscan. To compensate for delayThe value, the thickness (nm) measured at the time of correction in the C-plate direction was input into the Axoscan. The measurement wavelength was 550 nm.

< glass transition temperature (Tg) and Coefficient of Thermal Expansion (CTE) >

The film was cut into 5mm × 20mm to prepare a sample, and then the sample was loaded using an accessory. The length of the actual measured film is equal to 16 mm. The pulling force was set to 0.02N. The first warming step is carried out at a heating rate of 5 ℃/min from 100 ℃ to 400 ℃, then cooling is carried out at a cooling rate of 4 ℃/min from 400 ℃ to 100 ℃, and then the second warming step is carried out at a heating rate of 5 ℃/min from 100 ℃ to 450 ℃. The change in thermal expansion was measured using TMA (Q400, TA Company).

At this time, the inflection point shown in the temperature increasing section during the second temperature increasing step is defined as Tg.

< thermal decomposition temperature (Td 1%) and weight loss (%) >)

The temperature at which the weight loss of the polymer was 1% was measured in a nitrogen atmosphere using TGA.

The weight loss after holding at 350 ℃ for 60 minutes was measured.

The weight loss after holding at 380 ℃ for 60 minutes was measured.

< modulus, tensile Strength and elongation >

A film 5mm by 50mm long and 10 μm thick was stretched at a speed of 10 mm/min using a tensile tester (Instron 3342, manufactured by Instron) to measure modulus (GPa), tensile strength (MPa) and elongation (%).

< measurement of residual stress and bending value >

The resin composition was applied by a spin coater onto a 6-inch silicon wafer (the [ amount of warpage ] of the wafer having been measured in advance by using a residual stress gauge (FLX 2320 by TENCOR)) having a thickness of 525 μm, and cured in an oven (manufactured by Koyo Lindberg) at 250 ℃ for 30 minutes and at 400 ℃ for 60 minutes in a nitrogen atmosphere. After curing, a silicon wafer having a resin film with a thickness of 10 μm was produced. The warpage amount of the wafer was expressed as an actual bending value measured by a residual stress meter, and the residual stress generated between the silicon wafer and the resin film was measured.

[ Table 1]

[ Table 2]

[ Table 3]

[ Table 4]

As can be seen from tables 1 to 4, the polyimide film according to the examples had a modulus of 2.2Gpa or less, and appropriate rigidity and elasticity with an elongation of 20% or more by using DDS together with DPS-DMS as a diamine and adjusting the distribution ratio of pores in the polyimide film to 1% or less.

< Experimental example 2>

Each of the compositions prepared in example 9 and comparative examples 1 and 2 was spin-coated on a glass substrate. The glass substrate coated with the polyimide precursor solution was placed in an oven, heated at a rate of 5 ℃/min, cured at 80 ℃ for 30 minutes, and cured at 400 ℃ for 30 minutes to prepare a polyimide film.

The distribution ratio of the phase separation domains of the polyimide film was measured by the method shown in fig. 2. The FIB-SEM image of 100,000 magnifications was fixed at 100mm × 70mm, the image was subdivided into 2mm × 2mm, and the image was divided into white and black areas of 1750 total areas. The distribution ratio of the domains is calculated as the ratio of the white area to the entire area.

When the distribution ratio of the phase separation domains of example 9 was measured according to the above-described method, 650 white regions were present in a total of 1750 regions, thus indicating a distribution ratio of about 32% of the phase separation domains.

The membrane of comparative example 1 does not contain the DPS-DMS structure and thus does not exhibit phase separation as shown in fig. 3. In the membrane of comparative example 2, TFMB was used instead of DDS as diamine, and thus a large number of nanopores were generated in the membrane, and the presence of a phase separation domain could not be confirmed.

On the other hand, fig. 5 shows FIB-SEM images (× 100,000) of polyimide films according to example 11(DPS-DMS 15 wt%) and examples 13 to 15(DPS-DMS, 25 wt%, 20 wt%, 5 wt%, respectively). It can be seen that the phase separation domains are uniformly distributed with few pores in the membrane.

< Experimental example 3>

SiO was deposited on the polyimide films prepared in example 4 and comparative examples 2 and 4 at 350 deg.C₂. Mixing SiO₂The thickness of the layer is set to

Thereafter, SiO is formed thereon₂The polyimide film of the layer was heat treated at 380 ℃ for 2 hours.

FIG. 6 is a view showing SiO being formed thereon₂Photo of polyimide film of the layer. As can be seen from FIG. 6, SiO deposited on the films of comparative examples 2 and 4 having a distribution ratio of pores of 1% or more₂Cracks are generated in the layer. However, it can be seen that SiO deposited on the film having the presence of pores of 1% or less (e.g., 0.1%) as in example 4₂No cracks were generated in the layer.

While the present invention has been particularly shown and described with reference to particular embodiments thereof, it will be obvious to those skilled in the art that the detailed description is of preferred embodiments only, and that the scope of the present invention is not limited thereto. It is therefore intended that the scope of the invention be defined by the following claims and their equivalents.

Claims

1. A polyimide film comprising the product of polymerization and imidization of a polymeric component comprising: a diamine component comprising a diamine having the structure of formula 1 below and an amine-terminated methylphenylsiloxane oligomer; and

a dianhydride component containing two or more tetracarboxylic dianhydrides,

wherein a distribution ratio of pores in the film is 1% or less:

[ formula 1]

2. The polyimide film according to claim 1, wherein when a FIB-SEM image of 100,000 magnification of the polyimide film is fixed to 100mm x 80mm and subdivided into 2mm x 2mm, the distribution ratio of the holes is calculated as a ratio of an area in which the holes are present with respect to the entire area.

3. A polyimide film comprising the product of polymerization and imidization of a polymeric component comprising: a diamine component comprising a diamine having the structure of formula 1 below and an amine-terminated methylphenylsiloxane oligomer; and

a dianhydride component containing two or more tetracarboxylic dianhydrides,

wherein a plurality of domains derived from the amine-terminated methylphenylsiloxane oligomer are dispersed in a polyimide matrix derived from the diamine of formula 1, and the plurality of domains have an average size of 10nm or less:

[ formula 1]

4. The polyimide film according to claim 3,

wherein the distribution ratio of the domains is 25% to 60%, and,

wherein when a FIB-SEM image of 100,000 magnification of the polyimide film is fixed at 100mm × 70mm, subdivided into 2mm × 2mm, and each area is divided into a white area and a black area, the distribution ratio of the areas is calculated as the ratio of the white area to the entire area.

5. The polyimide film of claim 1 or 3, wherein the amine-terminated methylphenyl siloxane oligomer has the structure of formula 2 below:

[ formula 2]

6. The polyimide film of claim 1 or 3, wherein the dianhydride component comprises biphenyl tetracarboxylic dianhydride (BPDA) and pyromellitic dianhydride (PMDA).

7. The polyimide film of claim 1 or 3, wherein the polymeric component comprises 5 to 30 wt% of the amine-terminated methylphenylsiloxane oligomer, based on the total weight of the polymeric component.

8. The polyimide film of claim 1 or 3, wherein the polymeric component comprises 1 to 10 mol% of the amine-terminated methylphenylsiloxane oligomer, based on the total diamine component.

9. The polyimide film of claim 6, wherein the dianhydride component contains BPDA and PMDA in a molar ratio of from 6:4 to 8: 2.

10. The polyimide film according to claim 1 or 3, wherein the polyimide film has a modulus of 2.2GPa or less and an elongation of 20% or more.

11. The polyimide film of claim 1 or 3, wherein the polyimide film has a glass transition temperature (Tg) of 230 ℃ or greater.

12. A flexible device comprising the polyimide film according to claim 1 or 3.

13. A method for manufacturing a flexible device, comprising the steps of:

reacting a diamine component containing a diamine having the structure of formula 1 below and an amine-terminated methylphenylsiloxane oligomer with a dianhydride component containing two or more tetracarboxylic dianhydrides to prepare a resin precursor composition;

applying the prepared resin precursor composition to a carrier substrate;

heating and imidizing the resin precursor composition to form a polyimide film according to claim 1 or 3;

forming a device on the polyimide film; and the number of the first and second groups,

peeling the polyimide film having the device formed thereon from the carrier substrate:

[ formula 1]

14. A method for manufacturing a flexible device according to claim 13, wherein the method comprises one or more processes selected from LTPS thin film forming process, ITO thin film forming process, and oxide thin film forming process.